In general, a tire is formed of a plurality of rubber members for a tire and each portion such as an inner liner, a tread portion, a side wall portion and the like is formed of unvulcanized rubber according to characteristics required for each of them. The rubber members constituting each portion of the tire is formed by extruding the rubber member using a rubber extruder provided with a die in compliance with the sectional shape of the respective rubber members and cutting the extruded unvulcanized rubber into a predetermined length or wrapping it around a tire molding drum, for example.
FIG. 5 is a sectional view of a prior-art rubber extruder described in Patent Document 1.
This rubber extruder 100 includes a hopper 113 which inputs rubber together with a material to be kneaded, a screw 111 which transfers the rubber having been inputted into this hopper 113 while kneading it, a cylinder 112, a gear pump 122 formed of two gears 122a and bearings 122b thereof, and a die head 124 which forms the extruded rubber into a desired sectional shape.
In this rubber extruder, the rubber having been inputted from the hopper 113 is transferred by the rotating screw 111 and discharged into a rubber retaining portion 115, and the rubber having been retained in the rubber retaining portion 115 once is extruded by the gear pump 122 by a constant amount each into a predetermined shape through the die head 124.
A sample is taken in order to check the physical properties and states of the rubber extruded by the rubber extruder as above. Particularly, if ribbon-shaped rubber having a small width of 100 mm or less is to be continuously extruded, the line is stopped, and a part of the ribbon-shaped rubber is carefully cut out by using a knife by a manual work while attention is paid not to cut the rubber.
However, with such a method, the sampling work is cumbersome and moreover, since the line should be stopped, it is a cause to obstruct productivity improvement. Particularly, in a design in which a process of supplying rubber of a rubber extruder directly to a molding machine is adopted, since the rubber extruder cannot be stopped in the middle, there is a problem that sampling cannot be performed. Also, since the sampling relies on manual work, it is likely that troubles relating to the quality of a molded tire such that a cut-out sample is mistaken, the rubber type is wrong or the like can be induced, while workers should enter information relating to the cut-out samples one by one, which results in a problem of an increase in the number of working processes.
Here, regarding automatic sampling of extruded rubber, such a device is known which performs a series of operations in which a sample piece is taken from a continuously extruded rubber sheet and the sample piece is delivered to a measuring device (See Patent Document 2), for example.
FIG. 6 is a diagram schematically illustrating this sampling device.
In this sampling device 101, a rubber sheet G extruded from a rubber extruder (not shown) is made to pass between a cutter receiver 102 and a punching cutter 104 arranged above that and capable of elevation, and the cutter 104 is lowered so as to punch the rubber sheet G between it and the cutter receiver 102, and the punched rubber sheet G is contained in a cylindrical hole in the cutter 104 once, and then, the sample piece in the cylindrical hole is sucked by a vacuum pad 106 at a sample receiving position P1 immediately below the cutter 104, while sample receiving means 105 transfers this to a sample delivery position of a turn table 107 provided in a sample measuring means 103
However, this sampling device 101 basically replaces the prior-art manual work of cutting the rubber sheet G after being extruded by an automatic work by machine, and since a part of the extruded rubber sheet is cut out, the rest of the cut-out part remains as it is and moreover, a cutting device which cuts out and samples a rubber sample should be provided separately from the rubber extruder. Therefore, not only the cost but also the size of the device is increased, and there is another problem that a place for installing the cutting device is needed.